The present invention relates to a method of measuring the proportional consumption of energy usage in each unit of a relatively small multiple unit facility e.g. a multiple unit apartment dwelling or commercial building relative to all of the other units when operated from a single fossil fuel burning furnace.
In recent times, considerable emphasis has been placed on energy conservation as the result of rising energy costs and the depletion of fossil fuel supplies. Most of the energy conservation efforts have been made in industry as a result of governmental regulation in contrast to energy conservation based upon financial savings particularly from the individual consumer. In smaller size multiple dwellings operated from a single furnace which burns fossil fuel there is little, if any, motivation on the part of the consumer renting a given unit to limit fuel consumption since individual unit consumption of fuel is hard to measure. As a result the owner of the multiple dwelling includes the cost of energy consumption in the rental charge for the unit. It is not cost effective for an owner of a small building to install additional furnaces so that each unit will operate from its own furnace.
Watt hour meters are conventional and well known for measuring energy consumption from a source of electricity either to an individual house or building or to an individual appliance and from which the cost of electricity may readily be derived, see for example U.S. Pat. Nos. 4,814,996, 4,901,007, 5,089,771 and 5,315,236 relative to its use of a watt hour meter in connection with an appliance. However in connection with a small multiple dwelling which utilizes a single fossil fuel furnace to supply heat or air conditioning to each of its multiple units it is not known to date how to apportion or allocate cost attributable to energy consumption from each of the individual units. The reason for this is that there is, at present, no method to directly correlate the fossil fuel being consumed by the single furnace for which the owner of the facility is responsible and the energy consumption in each of the individual units for which the lessees are responsible over any given time period.
The present invention relates specifically to a relatively small multiple dwelling or building which employs a single furnace which consumes fossil fuel e.g., oil, wood or gas. The furnace will supply heat or air conditioning to each of the units either by the circulation of hot water through a radiator in each unit or by circulating hot air to each of the units using a separate blower for each unit. The hot water circulator in a "hot water system" or the blower for each unit in a "hot air system" are individually connected to a source of electricity through a relay switch of a thermostat located in each unit which is under the control of the unit renter. The method of the present invention utilizes an hour meter to determine the energy consumed in each of the units in proportion to the energy consumed in all of the other units of a multiple dwelling operated from a common furnace which consumes fossil fuel.